81. A collection of concepts that can be used to describe the structure of a database is :
(A) Data type
(B) Database
(C) Data model
(D) Data schema
Answer: (C)
82. To find the details of all employees where salary is above Rs. 50,000, which of the following tuple calculus expression is correct ?
(A) {t I EMPLOYEE (t) AND t. Salary > 50000}
(B) (Select EMPLOYEE (t) AND t. Salary > 50000}
(C) (Select EMPLOYEE AND Salary > 50000}
(D) All of the above
Answer: (A)
83. In ER-diagram, derived attributes are represented by :
(A) Dotted Oval
(B) Double Oval
(C) Double Dotted Oval
(D) Double Rectangle
Answer: (A)
84. Given the relational schenia R(A, B, C, D) and FDs A => B and BC => D. Determine which of the dependencies shown below cannot be derived from these FDs ?
(A) AC => D
(B) B => D
(C) AC => B
(D) Both (B) and (C)
Answer: (B)
85. A given population of events or items are partitioned into sets of similar elements is known as :
(A) Pattern with time series
(B) Clustering
(C) Classification Hierarchies
(D) Association Rules
Answer: (B)
86. A database which permits the database system to store history of changes and allows users to queiy both current and past states of the database is known as :
(A) Temporal database
(B) Spatial database
(C) Deductive database
(D) Expert database
Answer: (A)
87. Which of the following is also known as galaxy schema?
(A) Start schema
(B) Snow Flake schema
(C) Fact constellation schema
(D) Redundant schema
Answer: (C)
88. In data-warehouse data sources can be constructed using:
(A) Similar schema and data model
(B) Different schema and data model
(C) Similar schema and different data model
(D) All of the above
Answer: (D)
89. …………….. is the main file that drives the Map reduce process.
(A) Mapper
(B) Reducer
(C) Driver
(D) Executer
Answer: (C)
90. A database that has a set of associated triggers is known as :
(A) Active database
(B) Operational database
(C) Functional database
(D) Dynamic database
Answer: (A)
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